This invention relates to timing relays having motor drives in general and more particularly to an improved relay of this nature which is more compact and more reliable.
Timing relays using electric motor drives in which a clutched gear wheel is driven through gears by the relay motor and engages an indexing gear wheel when its drive shaft is properly shifted upon the switching on of the timing relay are known. In such arrangements, the clutched gear wheel and indexing gear wheel are disengaged after a preset delay time has passed. Furthermore, there is provided in such relays delayed actuation of at least one switching contact caused by a displaceably arranged actuating element spring coupled to a solonoid armature and having its displacement controlled by the indexing gear wheel.
Such a timing relay is known. In the known arrangement, shifting of the drive shaft is carried out by means of a spring loaded lever which is released by the relay armature when the timing relay is switched on. After the delay time has expired, the lever is swung back by an arm connected with the actuating element and the indexing gear wheel is thereby disengaged from the clutched gear wheel. Furthermore, a locking lever is provided which locks the actuating element in its starting position after the timing relay is switched on. Once the predetermined delay time has expired, the locking lever is shifted by the indexing gear wheel and releases the actuating element. Thereupon, the actuating element is displaced by the force of a spring which became tensioned when the armature of the solonoid was pulled in and switching contacts are actuated.
The arrangement of the lever for engaging the clutched gear wheel of the locking lever in this known timing relay requires a great deal of space. Furthermore, because of the large number of moving parts, its reliability is lowered.
In view of these deficiencies, the need for an improved relay of this nature which takes up less space and is more reliable becomes evident.